I have a little bit of money saved up for spring mods, my car will be back rolling Saturday after an Opti Replacement . I went with just the GM Unit because the MSD Pro-Billet won't be out for ahwhile yet, and I need my car back. Plus I plan on rebuilding everything, a year or two down the road when I get our of college, so I will ditch the opti.

Anyway, I plan on doing a few appearance mods, rims, tint etc. But as far as performance goes I will be installing Pacesetter Coated LT's, ORY, Hooker Catback, a Fuddle 2800 RPM Stall, Tranny Cooler, and 3.42's. I might do a cut out as well. But I'm wondering how much I would be gaining by doing a Holley 52mm Throttle Body, I know our stock LT1 TB's are pretty good, but would it be worth the $350 to upgrade to the Holley if I'm doing the rest of the mods to it?

 

Your going get mixed reviews about it some will swear it took a tenth or two of their 1/4 mile e.t, some will say that its not a restriction until 500hp and is worth nothing. If you were going to upgrade I suggest at least getting a 58mm and porting out the intake yourself. In my opinion I would put that money else were like lower control arms or any type of suspension. I feel the money could be spend better somewhere else and for the money it isn’t a good mod but if you are dead set on getting one or feel like the other people I would say at least go with the 58mm. Hope this helped.

 

Unless youre getting into the engine, a 52 or 58 mm TB is going to be overkill.

 

Im going with almost the same setup come spring, except for a 3000 or 3200 stall and 3.73 gears. Ive asked the same questions about the TB's and everybody said it was a waste of money and was overkill for this setup, like said above. But im sure other people think any bolt-on is worth it, just to get that extra few ponies...

 

actually the MSD opti is available. Well you can order it atleast

http://store.summitracing.com/partde...5&autoview=sku

IMO you don't need to upgrade your throttle body until you start seeing an intake restriction, in the form of vacuum at WOT, on your car. I would think the general rule would be anything over 2" at WOT means something is causing an intake restriction.. I've read a few articles that state the 52 and bigger TBs are for any car that's shifting over 4800rpm.

Matt

 

I never saw a gain from it on my WS6 until I hit over 325hp on the dyno. I swapped it on and off with the stock one several times before and after different mods that I did to see where or if it made a difference. It would not be worth it for you with the other mods you listed.

 

Absolutly not!! I made 365 to the tire with the stocker, 364 with the 52mm BBK.

 

You've got to look at the big picture. It in itself doesn't represent any significant gains, but a part of the combination, it's worth something.

 

Don't need a throttle body till you at least have a cam, i made 378RWHP with a stock TB on heads and cam car and 391RWHP with a 52mm on it.

 

Here is a little food for thought.... Assuming you have some very good flowing heads and obviously the cubic inch for an lt1 motor is about the same as the ls1 motor. All else being equal .... Why did the factory put 80mm t.b. on stock ls1s.To add to this I am sure there are plenty of lt1 motors in here with ls1 stock hp and torque and better, but 58mm seems to be the limit other than the monoblade that rarely gets mentioned. Btw the the ls1 guys are porting there 80mm and picking up about 12 hp(peak) and 90mm t.b. are saleing like hot cakes. I have a ls1 car but I also have a 87 iroc with a mini ram(lt1 intake plus) which is as close as I can come as far as a comparison.I know the ls1 is an 18 degree motor , but what else dictates stock ls1s to have 80mm???

 

Assuming that the tune is spot on, it takes a lot to max out the stock throttle body on both the LT1 and the LS1. There was a Top Stock LS1 running 9.4's with the stock throttle body at Rockingham during the Finals.

Daren

 

I hear you but why did the factory use 80mm and guys getting improvements from porting and 90 mm???

 

we swapped one out on my buddies car on the dyno, he gained like 9 hp
that was going from a stock to a 58 on a bolt on car with the 305 cam.

it was 9 hp all the wall up the power band so thats a pretty good increase.

 

It doesn't sound like the throttle body would be worth the money, unless I decide to go heads/cam, then I would do a 58mm. Thanks for the info, I will skip that mod and spend the money elsewhere.

 

I think that the biggest difference is the use of aftermarket computers and the amount of time spent on the tune?
I think that the same 48mm throttle body is used on the GMPP Ram Jet 502/502?

Daren

 

what about with a supercharger? im sure a 52mmTB would give something correct?

 

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More than likely, but the question I really wanted to know... was will just a 52mm give me significant power gains... and the answer is no. After I get out of college, I plan on rebuilding, and going 383 LT1, ProCharged, 12 Bolt, 3.73's or 3.42's, the works... but until then, I probably won't mess with too much. LT's, Stall, Gears, and some look cool, sound cool mods. But watch out for Me when I got the budget.

 

Well if you want a used 52mm I have one.. its in great shape and the gain may be worth a 175.00 rather than 350.

 

Correct me if I am wrong but the LS1s use a SINGLE BORE TB where the LT1 use a two bore. The 80mm is 5026 sq. mm a 90mm is 6361, a 48mm DUAL bore LT1 tb is 3618 a dual 52mm is 4246 and a 54mm is 4580 and a dual 58mm is 5284. How high the engine revs and plenum volume have to be considered too. I can tell you this in a swap from a foiled 48mm to a 58mm on my mildly cammed LT1 at WOT I could tell no difference through SOTP or Datamaster, though it made light throttle drivng quite different and the car is a royal PITA to drive in the snow now since slight throttle movement results in a lot more airflow.

 

My car with just bolt on's picked up .2 and 2 mph with a swap to a 52mm TB in the 1/4. I dont care if it picks up 2 hp or loses 5 on the dyno, it made it go faster at the track.